Determination of Effective Reaction Coordinates and the Schematization toward Reaction Designing

2018 Fiscal Year Final Research Report

• Project/Area Number: 15KT0065
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Multi-year Fund
• Section: 特設分野
• Research Field: Transition State Control
• Research Institution: Hiroshima University
• Principal Investigator: KOHGUCHI Hiroshi 広島大学, 理学研究科, 准教授 (40311188)
• Project Period (FY): 2015-07-10 – 2019-03-31
• Keywords: 状態選別分子衝突 / イオン・分子反応 / 散乱法 / 低温化学

Outline of Final Research Achievements

A molecular collision apparatus which controls internal degrees of freedoms of reactants as well as the translational energy has been built. Merging-beam experiments for ion-molecule reactions were carried out. Quantum effects on the reactivity, which was expected under a low collision energy condition, was not observed. We localized the technical problem; the slow ions with too high concentration generated with a focused laser beam significantly loose the intensity. An ion-imaging detector was introduced to obtain high sensitivity for a low concentration ion beam, whose translational energy resolution is kept narrow. We organized the collaboration to have technical supports for the slow ion control. In the collaboration, we measured the high-resolution spectra of O2H+ and CH3+ ions with an ultracold trap, which utilizes the same deceleration device as that with the developed apparatus. The spectral analysis yielded characteristic interactions in ion chemistry.

Free Research Field

化学反応論

Academic Significance and Societal Importance of the Research Achievements

イオン・分子反応は、一般に低温条件ほど反応性が高くなるといった特徴的なエネルギー依存性を示す。分子間の衝突エネルギーに比べて、反応分子内の特定された振動・回転状態の励起エネルギーが高い反応条件では、高効率でかつモード選択的な反応制御が期待できる。本研究では、振動・回転自由度および並進運動を制御したイオン分子ビームを利用する反応実験装置を開発した。また、イオンの低速制御機構を使って行った極低温分光実験では、星間分子としての存在が予測されてきたプロトン化酸素をはじめて分光学的に同定した。これらの成果は、並進制御を利用した分子イオンの分光学と反応論に関する特色のある研究成果として位置づけられる。